538 BRITISH FOSSIL REPTILES. 



part of the bone and may have served to lodge and facilitate the movements of a 

 cyhndrical protrusile tongue. The character of the palatal surface of the upper jaw is 

 exemplified in Pterodadi/lus Cuvieri {Pter., PI. 3, fig. 4) ; in PterodadyJus compressi- 

 rostris (ib., ib., fig. 10) ; in Pterodadylm Sedgioiddi [Pter., PI. 7, fig. 1 b) ; and in 

 Pterodadylus clavirostris (PI. I, fig. 4, of the present section). The grooved character of 

 the oral surface of the mandibular symphysis is shown in Pterodadylus SedyioicHi {Pter., 

 PI. 7. fig. 2 h). 



The angle of convergence of the two rami of the lower jaw to the symphysis in 

 Pterodadylus sayittirostris {Pter., PI. 18, fig. 8) renders it improbable that the sides of 

 that symphysis would run parallel for the extent shown in ib., PI. 19, fig. 6, or that the 

 symphysis would terminate so obtusely. Moreover, the five pairs of sockets, with bases of 

 teeth, in the fossil representing Pterodadylus Baviesii, indicate teeth of smaller size and 

 closer disposition than in the mandible of Pterodadylus sagittirostris. The foremost 

 pair of sockets (ib., figs. 5 and 6, a) are less elliptical than the rest. The base of the 

 tooth retained gives an almost circular section ; the outlet of the socket is directed more 

 obliquely outward than those of the others, and the crowns of the teeth were, probably, 

 more divaricated in this foremost pair. The sections of the bases of the teeth in the 

 sockets h — e give a fuller ellipse than the outlet of the sockets themselves. The outer 

 surface of the bone is smooth and even, the upward curve from the under margin of the 

 symphysis is gradual, as shown in fig. 5. 



This specimen was discovered in the ' Gault ' at Folkestone, by Mr. William Davies, 

 of the British Museum, to whom, in acknowledging much useful assistance, I have 

 pleasure in dedicating the species of Pterodactyle indicated by the present fossil. 



§ 2. Pterosauria from the Wealden. 

 A. — Pterodadylus sagittirostris, Owen {Pterosauria, Plate 18, figs. 1 — 8). 



The type of Cuvier's gen>is Pterodadylus is the species which he calls longirostris. 

 The chief generic character is the extreme length of the fourth digit of the fore-limb.^ 



The Pterodadylus longirostris, Cuv., is characterised, as the term implies, by long, 

 slender, tapering jaws, armed along their anterior half by numerous long, slender, 

 pointed, separated, and pretty equally distant teeth. 



In a general way the portions of mandible about to be described repeat these 

 characters. The mandibular teeth appear to have been about the same in number. 

 Nineteen are reckoned by Cuvier to have occupied the deutigerous part of each mandi- 



1 " Un genre de Sauriens, caracteris6 par I'excessif allongement du quatrifeme doigt de devant, auquel 

 nous avons donne le nom de Pterodactyle." — ' Ossemens Fossiles,' torn, v, pt. ii, 4to, 1S24, p. 358. 



